Thanks, @Fish Folko I really appreciate you sharing your set up. I would be interested in hearing how you harvest infusoria from your sponhe filters. I've had trouble getting infusoria cultures started. They all seem to just turn to Green water or simply never grow any infusoria. I've got two tanks that run sponge, though, so that may be helpful.
Also, thanks for the tips about Greg Sage. I've bought levamisole from him but I didn't think to reach out to him.